codeigniter input required function in php

The "required" function in CodeIgniter's Input class specifies that a form field must contain a value. If the field is empty, the form validation will fail. Here's how to use it:

$this->form_validation->set_rules('username', 'Username', 'required');

Explanation: - $this->form_validation->set_rules() is used to set validation rules for a form field. - The first parameter 'username' is the name of the form field. - The second parameter 'Username' is the human readable name of the field. - The third parameter 'required' specifies that the field must contain a value.

This ensures that the 'username' field in the form is required and must have a value for the form validation to pass.